New wiring harness help

[425HP409]

I installed a 396 in place of the original small block. The new engine wiring harness has this pink wire in the harness near the left temp sender. I can’t figure what it is for as the green temp sender wire is there for the sender.
ps: the photo reversed itself.

[steveo70]

On my American Autowire kit, the pink wire was for the HEI distributor I used.

[IIGW]

Originally Posted by steveo70

the pink wire was for the HEI distributor I used.

yessir

since the dawn of time the pink should be power to distributor.

check it with a testlight

[pjmoreland]

That's not the right kind of connector for HEI. If you ordered a harness for a truck with A/C, then that wire may be for a carb-mounted idle stop solenoid that bumps up the engine RPM when the A/C compressor is engaged.

[71CHEVYSHORTBED402]

What Moreland said. Though I thought it was for a anti-dieseling. Regardless, I cut it off. The connector for HEI is white.

[kwmech]

Don't cut it off directly. Follow it back to the bulkhead connector and remove the wire there

[425HP409]

Thanks for the info, I will check to see when it has power. It is too short to reach back to the HEI. It comes out of the loom between #3 and #5 cylinder, so I am leaning to a carb solenoid. I will report back.

[MikeB]

Originally Posted by 71CHEVYSHORTBED402

What Moreland said. Though I thought it was for a anti-dieseling. Regardless, I cut it off. The connector for HEI is white.

White is the tach feed, unless the truck's wiring has been messed with by a previous owner.

I would not suggest cutting off a connector unless you are absolutely sure you'll never need it.

[71CHEVYSHORTBED402]

Originally Posted by MikeB

White is the tach feed, unless the truck's wiring has been messed with by a previous owner.

I would not suggest cutting off a connector unless you are absolutely sure you'll never need it.

You're right, I should be careful. Harnesses vary by year and requirements. My replacement engine harness for HEI is 12 AWG pink wire with a white connector, runs from IGN to BAT. I'm 80/20 the wire on topic is for anti-dieseling. Make that 70/30 Good thing I didn't need it. Mine had to route to the RH side for a temp sender, because the plug in the LH head is frozen for a BBC, didn't prepare for that. The harness' layout ends up cleaner, though I may? have requested a longer temperature wire.

Originally Posted by 425HP409

I checked it and it has key on power and will reach to the carb where an anti dieseling solenoid would have been installed. Now I have an extra power lead if I ever need one.

Great. Now I'm 98/2 it's for anti-dieseling I'd like to see one set up, but can't find it.

[dmjlambert]

Another thing to get switched power in the area of the carburetor is carburetor-mounted TH400 transmission kickdown switch. I would think the manufacturer of the new wiring harness should be able to tell exactly what they intended you to use that plug for.

[RustyPile]

A good rule of thumb when installing aftermarket products.. When all else fails, read the instruction manual.. In other words, contact the manufacturer..

[71 super]

The Pink wire is for the fast idle solenoid located at the front of the carb. It is the single spade plug- pink wire, purpose is to kick up fast idle when A/C is running. It is shrouded in the asphalt loom to protect from heat generated on intake manifold. The correct solenoid /bracket and screw can be a difficult find if missing. There is a an aftermarket delco type that is shorter but serves the same function. it may also have the bracket as well. The plunger is adjusted via the nut at the head of the solenoid to increase rpm at idle a few 100 rpm while air is on.

[MikeB]

Originally Posted by 71 super

The Pink wire is for the fast idle solenoid located at the front of the carb.

I forgot about that! They're also available for Holley and Edelbrock carbs, but are ridiculously expensive.

[damnyankee36]

I had the same question a couple of months ago.

https://67-72chevytrucks.com/vboard/...d.php?t=848442

The original harness had the same connector. The truck was already partially torn apart so I couldn't verify where it went to. As suggested by others it could be used as an idle stop solenoid, but not for the AC kickup as it's always powered when the engine is running. I don't know why such a large gauge wire would be needed for that function.

It is connected to the same terminal at the firewall bulkhead connector as the coil resistor wire. My plan is to cut open that part of the harness and reroute it for use with the HEI.

[425HP409]

I checked it and it has key on power and will reach to the carb where an anti dieseling solenoid would have been installed. Now I have an extra power lead if I ever need one.

[damnyankee36]

Just remember, it's unfused.

[schovil69]

I used that wire for an electric choke.

[425HP409]

Originally Posted by schovil69

I used that wire for an electric choke.

That is a good use for it.